On a chilly day in late winter, Grayson sits in his fifth-floor office in the gleaming Robert H. and Clarice Smith Building on the East Baltimore campus, explaining his research. Photographs of two of his role models, President Barack Obama and the boxer Muhammad Ali, hang side by side on one wall.

The slim, soft-spoken tissue engineer, the father of five school-age children, is married to Catherine Sewell, a gynecologist and medical officer at the Food and Drug Administration. He was born in Arima, a city of 33,000 on the island of Trinidad, where both his parents were teachers who rose to become high school principals. As a student, he says, he loved math, physics, and chemistry, and early on decided to become an engineer. Since most engineers in Trinidad and Tobago work in the oil and gas industry, that’s where he assumed he would end up.

But during soccer practice one day when he was earning his engineering degree at the University of the West Indies, the slim midfielder tried to cut between two defenders, planted his foot wrong, and tore the meniscus in his right knee.
A piece of cartilage lodged itself in the joint, making it impossible to bend his knee. An orthopedic surgeon studied the knee and leg muscles, twisted Grayson’s ankle, and popped the torn meniscus out. “At the end of that session, I was able actually to walk out of the office,” he says.

It was a painful but inspiring demonstration, Grayson says, of how an injury could be treated as an engineering problem. “What was enthralling was watching the doctor,” he says. “Being able to see what a doctor does and how a doctor can impact a patient’s life—I think that was the part that stood out to me.”

After considering medical school, Grayson instead became the first doctoral student in the biomedical engineering program at Florida State University, where he focused on how 3-D environments and oxygen levels inside the body influence the development of mesenchymal stem cells, which hold the potential to differentiate into a variety of cell types, including bone, cartilage, and muscle cells.

After earning his PhD, he completed his postdoctoral fellowship at Columbia under Gordana Vunjak-Novakovic, who says she was impressed by Grayson’s maturity and ambition. His research focused on developing a bioreactor to help stem cells build an anatomically precise temporomandibular joint. The jaw’s connection to the skull, it is crucial to chewing and speaking.

While making bone tissue with stem cells is one thing, making it with a precise shape is another. “He really started from scratch,” says Vunjak-Novakovic. “Before, we had the technology for engineering bone, but nothing like anatomical bone. This was never done before.”

When Johns Hopkins offered him a job in 2009, he jumped at the opportunity. His goal, he says, was to translate his research from the bench to the operating room, which he saw as Johns Hopkins’ great strength. “That’s a critical element that attracted me to come to Baltimore,” he says. He adds, half-jokingly, that previously he had spent his career moving north from the equator—from Trinidad to Florida to New York City. “So I was happy to come back toward the south,” he says, smiling.